1. Field of the Invention
The invention relates to feed guide stops for positioning sheet products and to the assembly provided with such feed guide stops.
2. Description of the Prior Art
The invention relates more particularly, but not exclusively, to feed guide stops, for positioning sheets of paper or cardboard in printing machines. Such stops may be found on feed tables for a printing and/or cutting press or devices for stacking sheets exiting from this press.
In these assemblies, it is common practice, as described for example in French Pat. Nos. A 2,277,727 and 2,308,576, to fix edgewise in their frame guide stops against which the sheets come to a stop, depending upon the type of assembly considered, prior to being taken and carried to the press and/or to complete their being placed in the stack.
It stands to reason that these guide stops all act in a common plane corresponding to that of the sheet to be positioned and in which plane they each follow one of the edges of said sheet which, for example, if it is rectangular, will thus call upon front and side guide stops. Needless to say that in order to be able to adapt to the different formats likely to be used in at least one of the machines placed downstream and/or upstream of the positioning assembly, while continuing to act in the same plane, it must be possible to position these guide stops in the frame of said assembly in accordance with the formats used.
To accomplish end positioning, the front and side guide stops are usually connected to front and side supports which, advantageously, are placed in the assembly at different levels so as to be able to fix them in the frame without interfering with one another. When fixing such supports in the frame, one can call upon known fixing means which are known in the art, such as clamps or sliding blocks, each of which cooperate with one of the positionable slide bars or guide rods carried by the frame and which are controlled separately, for example, by flywheels which set in motion nut/bolt or rack-pinion systems under the possible control of a vernier. In order to freely intersect at different coordinates dictated by the different formats of the sheets, the supports can be placed at different levels. The same, however, does not hold true for guide stops which, as already mentioned above, necessarily must all act in the same plane. Because of this operational requirement, in prior art structures which utilize guide stops, the guide stops cannot intersect. At each point of intersection, movement or operation of at least one of them must thus be interrupted locally in order to let the other pass. Thus, for each of the formats, at least one of the guide stops must be specially constructed.
Needless to say, this results in a cost increase for the necessary components of the machine and in an increase in the time lost for preparing machines to a new format, because of the need to disassemble the old guide stop and fix the new one in place.